Blackphone SSL security flaw was patched within days, says CEO

John E. Dunn |
Sept. 11, 2014

Researchers checking out the $629 (£390) Blackphone ultra-secure Android smartphone recently found a potentially significant vulnerability that could have allowed an attacker to carry out a man-in-the-middle (MitM) to sniff the login credentials for the device's Silent Circle apps.

Researchers checking out the $629 (£390) Blackphone ultra-secure Android smartphone recently found a potentially significant vulnerability that could have allowed an attacker to carry out a man-in-the-middle (MitM) to sniff the login credentials for the device's Silent Circle apps.

The now-patched flaw discovered by Bluebox Security was a relatively straightforward if surprising one to do with the way the Blackphone was found to be implementing SSL security for its cornerstone apps, Silent Phone, Silent Text, Silent Contacts, Secure Wireless and SpiderOak.

The researchers were able to load their own SSL root certificate on the phone, tricking all four into revealing their credentials in the clear. It's disappointing that such a basic flaw should appear on this kind device although it has been patched by implementing SSL pinning, a way of hardcoding certificates between the app and the server.

The team also noticed a few other Blackphone wrinkles, including that the certificate store on the device included over 150 root certificates, including one described as being for undetermined 'Government' that has to be manually disabled.

There was also no way to update apps one by one - a more time-consuming firmware update for the whole OS is still required although Blackphone confirmed it plans to implement a fix for process in the near future.

Given that it shipped as recently as 30 June, the Blackphone is still a work in progress, something maker SGP Technologies (the Silent Circle-Geeksphone joint venture) openly admits. Impressively, the SSL pinning was fixed by 26 August in the form of PrivatOS 1.0.3, only 11 days after Bluebox privately disclosed the issue.

"We see this report as validation of our process. We are proud that we can engage with the research community," SGP technologies CEO, Toby Weir-Jones told Techworld. "The turnaround has been prompt."

The firm has today released another firmware update, PrivatOS 1.0.4, which implements a number of other bug fixes and updates, he said.

With a two-year subscription for Silent Circle apps built into each Blackphone, Weir-Jones remains upbeat about the keen interest certain types of user feel for the device's stripped-back and hardened approach to Android security. He plays down the whole anti-NSA snooping angle that some commentators used to anchor the Blackphone concept when it was first announced.

The need of users was simpler. "We are giving them an alternative to the status quo phones," he said.